The so-called Body Mass Index (BMI), is used today to define the degree to which one is overweight. BMI is calculated by dividing body weight in kilograms (kg) by the square of the body height in meters (m2). A BMI of more than 40 corresponds to morbid obesity. A BMI of 35-40 is defined as severe obesity and a BMI of 30-35 is defined as obese. Morbid obesity and, to a lesser extent, severe obesity of human beings results in a number of health consequences such as cardiovascular diseases, diabetes and damages of the locomotor system.
As a general rule, in the case of extreme forms of obesity, often only a few kilograms of weight reduction, which is hardly noticeable, is achieved over the long run despite all efforts. In such extreme cases, surgical therapy is often finally indicated.
Nowadays, surgical therapies for the morbidly obese include performing operations for restricting the stomach. Among these, “gastric banding” and the “gastric bypass”, in which appropriate implants are inserted, have been generally accepted.
Gastric Banding
With this operation the inlet area of the stomach is constricted by an implanted synthetic band, thereby forming a smaller upper stomach sac which communicates with the remaining stomach area only through a small outlet.
However, this operation can result in the patient eating more high-caloric food after the operation or the constricted stomach bag bulges and expands so that a certain increase in weight is probable again. Moreover, it is possible for the silicone band to be displaced or break through into the stomach.
Gastric Bypass
By this operation a smaller stomach bag in the inlet area of the stomach is likewise separated from the main portion of the stomach, defined with the aid of clip suture instruments. However, this stomach bag does not communicate with the remaining stomach area, but with an anastomosed loop of the small intestine which is pulled up and fixed to the stomach bag. The food passes through the esophagus and the smaller stomach bag and then flows into the loop of the small intestine, bypassing the remaining larger portion of stomach and much or all of the duodenum. Gastric bypass generally results in a higher reduction of weight than the gastric banding.
However, the operation is deemed to be irreversible, which is a drawback in the case of complications such as malabsorption consequences. Furthermore there is a risk that sutures at the clip suture instruments become leaky, thereby necessitating a further surgical procedure.